Labuschagne has scored one hundred in his last 49 innings and managed 20 in the opening Test against Sri Lanka, while teammates Usman Khawaja, Smith and Josh Inglis smashed hundreds.
"I can't see the top six changing, I daresay that'll be the same," Smith, leading the team in the absence of regular skipper Pat Cummins, told reporters on the eve of the second and final Test.
"(Labuschagne) played nicely at the back end of the summer, he looked like he was putting the pressure on the bowlers a little bit more.
"The more difficult the wicket is in terms of how much it's spinning, the more aggressive you have to be with your batting and the more proactive you have to be.
"He understands that, he understands spin and angles as good as anyone. I don't think he's far away from a good score."
Australia, who won the opening Test by an innings and 242 runs, are waiting to finalise their playing XI and Connolly could replace left-arm spinner Todd Murphy in their spin attack.
"It's possible, all options are on the table," Smith said.
"We're going to leave it late but we've got the resources here if we need."
Spin twins Matt Kuhnemann and Nathan Lyon destroyed Sri Lanka in the opening test, also at Galle, and they have part-time spin options in Travis Head and Beau Webster.
"(He's) another batter that bowls more than handy spin and spins the same way as Kuhnemann. We've got a few that go the same way as Nathan and Todd," Smith said.
"We're going to leave it until the last minute (to decide)."